Catalyst combination and a process for preparing linear, isotactic polymers

ABSTRACT

The invention concerns a catalyst combination for preparing linear isotactic polymers, wherein said catalyst combination contains a metal complex and an activator and a process for preparing linear, isotactic polymers which have a structure of which the tacticity varies within the range of between 25 and 60% of [mmmm] pentad concentration, an arbitrary or rather regular sequence of isotactic and atactic blocks being excluded, in which process a C 2  to C 20  olefin are reacted with the catalyst combination.

[0001] The present invention relates to a new catalyst combination and aprocess for preparing linear, isotactic polymers, wherein theisotacticity of the linear polymers due to a statistic distribution ofstereoscopic errors in the polymer chain, being within the range of from25 to 60% of [mmmm] pentad concentration.

[0002] For a long time, isotactic polymers have been of interest asplastic materials for manufacturing articles of relatively gooddeformation resistance, such as e.g. sheathings of household appliances.In general, such isotactic polymers with propylene as monomer are ofhighly crystalline nature and, therefore, relatively hard with little orno impact resistance at all so that they will come into question onlyfor application fields in which those characteristics are desirable.

[0003] Most recently, various attempts have been made, aiming atpreparing also polypropylene with elastic characteristics. EuropeanPrinted Publication 0 707 016 A1 specifies a catalyst composition and aprocess for preparing polyolefins. The catalysts specified in EuropeanPrinted Publication 0 707 016 A1 are, in substance, made up of ametallocene compound having an indene ring and a fluorene ring which arebridged via C, Si or Ge. In case of the metallocene compound, it, inthis connexion, is obviously essential that, in the indene ring system,at least the residue denoted with R⁴ not be hydrogen. When that residueR⁴ is hydrogen, the effects, such as specified in the aforementionedEuropean Patent Application, will not be attained (P 6, from L 57 up toP 7, L 3). The polymers specified in European Printed Publication 0 707016 A1 and prepared with metallocenes, here especially the polypropyleneprepared with those metallocenes, however, show as can be drawn from theexamples and the graphs, but unsatisfactory characteristics in regard ofthe elastic behaviour.

[0004] Departing from all these facts, it is the object of the presentinvention to find a new catalysator combination and to suggest a processto make polymers from olefinically unsaturated compounds available, notonly showing thermoplastic but, at the same time, thermoplastic-elasticcharacteristics and, thus, being applicable for many application fields.

[0005] That object is, in regard of the catalysator combination, solvedby the characterising features of claim 1; in regard of the process forpreparing the polymers, it is solved by the characterising features ofclaim 5.

[0006] The invention relates to a new catalyst combination containing ametal complex and an activator.

[0007] The metal complex is a metallocene compound. Herewith, metalcompounds of the Fourth Auxiliary Group of the Periodic System Table IVBgenerally come into question, which compounds may be present as definedmetal complexes and with which compounds activators are mixed. Ingeneral, the metals are present in the complexes in formally positivelycharged manner.

[0008] As regards the metals, titanium, zirconium, hafnium, vanadium,niobium, and tantalum specifically come into question, the metal atompreferably showing halogen or a C₁-C₈ alkyl, aryl or benzyl as residueX.

[0009] The metallocene is defined by general Formula I.

[0010] wherein the residues R¹-R⁷ are a linear or branched C₁-C₁₀ alkyl,a 5-7-linked cycloalkyl that, in its turn, may carry one or severalC₁-C₆ alkyl residues as substituents, a C₆-C₁₈ aryl, aryl alkyl or alkylaryl, in which case R¹, R²; R³, R⁴; and R⁶, R, here again, may bepartially or simultaneously integrated into 5-7-linked cycloalkyl oraryl rings fused thereto.

[0011] In case of the metallocene compound according to general FormulaI, it is essential that, in general Formula I, the carbon atom adjacentto the residue R⁷ and the carbon atom adjacent to the residue R⁶ be,with the indene ring system, only hydrogen. Thereby, it is ensured that,with the indene ring system, a linear system can form by the residues R⁶and R⁷, which system, obviously, will prove to be especiallyadvantageous when preparing the isotactic elastomers according to theinvention. In contrast to the metallocene complex according to EuropeanPrinted Publication 0 707 016 A1, only hydrogen atoms and no carbonatoms with further residues, as is imperative in the aforementionedEuropean laying-open specification, can, thus, be found at the positionsmentioned in the aforegoing.

[0012] In this connexion, suitable bridging structural units E are1.2-ethyl, 1.3-propyl, 1.4-butyl, carbon, silicon or germanium. For thecase that E is carbon, silicon or germanium, the bridging structuralunit E may, herewith, additionally carry the residues R⁹ and R¹⁰ which,then, are a C¹-C₈ alkyl, a 4-7-linked cycloalkyl or aryl, R⁹ and R¹⁰being able to also form a 4-7-linked cycloalkyl or aryl jointly with E.

[0013] A particularly preferred embodiment of the invention resides inthat such a metallocene complex is used as reflected by general FormulaVII.

[0014] wherein all the residues have the significations indicated above.In contrast to the metallocene complex according to general Formula I,it, however, now is imperative here on the indene ring system thatanother ring fused thereto be at hand which is bridged via two E²groups.

[0015] E₂ therewith, signifies CH₂, oxygen or sulphur and n is 1 or 2.

[0016] As defined in patent claim 1, it certainly is furthermoreprovided in accordance with the invention, to additionally use at leastalso one activator, apart from the metallocene compounds specifiedabove. The invention, herewith, generally encompasses all the activatorsthat have as yet become known in the state-of-the-art for metallocenecompounds. Such activators have also been specified by European PrintedPublication 0 707 016 A1. As activator, at least one compound of generalFormulas II to VI is, however, used with special preference.Accordingly, the activator may be an open-chain or cyclic alumoxanecompound of general Formula II or III, such as is reflected hereinafter:

[0017] wherein R⁸ is a C₁-C₄ alkyl group and n is a number between 5 and30.

[0018] In case of the catalyst combination according to the invention,also the above-specified compounds of general Formulas II and III can,alone or in combination with the subsequent activators such as arereflected by general Formulas IV to VI, be used.

B(C₆F₅)₃   (IV)

R⁹ ₃C[B(C₆F₅)₄]  (V)

[R⁹ ₃NH][B(C₆F₅)₄]  (VI)

[0019] In general Formulas IV to VI, R⁹, in this connexion, signifies aC₁-C₄ alkyl group or an aryl group.

[0020] It has, therewith, proven to be especially favourable when themetallocene complex according to general Formula I and the activatoraccording to general Formulas II to VI are employed in such quantitiesthat the atomic ratio between aluminium from the alumoxane or boron fromthe cationic activator and the transition metal from the metallocenecomplex is within the range of from 1:1 to 10⁶:1.

[0021] The invention furthermore relates to a process for preparinglinear, thermoplastic-elastic polymers from olefinically unsaturatedcompounds with an isotactic arrangement of the monomer unit and astatistic distribution of isolated stereoscopic errors along theindividual chains, tacticity varying within the range of between 25 and60% [mmmm] pentad concentration. A regular sequence of isotactic andatactic blocks, therewith, is excluded. In many cases, it was found thatthe [rmrm] pentad was totally missing or present with a maximum of 2.5%of the entire pentad area. Furthermore, it became evident that, in mostcases, the [rrrr] and [rrrm] pentads are always greater than the [rmrm]pentad. The process according to the invention is specificallycharacterised in that a specially selected catalyst combination is usedas described before.

[0022] Pressures of from 1 to 100 bars, preferably of from 3 to 20 barsand in particular of from 5 to 15 bars, have proven to be suitablereaction parameters for preparing the linear, thermoplastic, elastomericolefin polymers. Favourable temperatures are within the range of from−50° C. to 200° C., of preference at from 100 to 150° C. and of highpreference at from 20 to 50° C.

[0023] The polymerisation reactions can be carried out in the gas phase,in suspension and in supercritical monomers and especially in solventsinert under polymerisation conditions. In particular the solutionpolymerisation has proven to be the clearly superior thing for thepresent preparation process. Suitable inert solvents for that purposeare such solvents that do not contain any reactive groups in themolecule, i. e. aromatic solvents like benzole, toluol, xylol, ethylbenzole or alkanes such as e. g. propane, n-butane, i-butane, pentane,hexane, heptane or mixtures thereof.

[0024] The polymers prepared according to the invention are linear,thermoplastic, elastic polymers from an olefinically unsaturatedcompound with an isotactic arrangement of the monomer units and astatistic distribution of isolated stereoscopic errors along theindividual chains and a mean molecular weight Mw of the polymers withinthe range of from 100,000 to 800,000 gms/mol and a TG of from −50 to+30.

[0025] With the polymer prepared according to the invention, it isessential that the stereoscopic errors be situated in the polymer chainitself and that, thus, a specific pentad concentration result. In thisconnexion, it was found that, with the polymers prepared according tothe invention, the [rmrm] pentad with a maximum of 2.5% of the entirepentad area will, in general, be present. In many cases, it was alsofound that that [rmrm] pentad was completely missing.

[0026] Furthermore, it became evident that, in most cases, the [rrrr]and [rrrm] pentads are always greater than the [rmrm] pentad.Determination of the pentad concentration in case of polymers has,properly speaking, become known from the state-of-the-art and isspecified e.g. in J. A. Ewen, “Catalytic Polymerisation of Olefins”,Eds. T. Keii, K. Soga; Kodanska Elsevier Pub.; Tokyo, 1986, P 271 etseqq. Also the pentad concentration determination according to theinvention now present was carried out by means of the method specifiedin the above-mentioned piece of pertinent literature.

[0027] Apart from the above-mentioned specific pentad concentration, thelinear, isotactic polymers have a molecular weight within the range offrom 100,000 to 800,000, of preference from 110,000 to 500,000 and ofspecial preference within the range of from 120,000 to 300,000 gms/mol.The mean molecular weights Mw (mean weight value) of the polymers weremeasured by means of the gel permeation chromatography (GPC) method at135° C. with microstyragel as column material and 1,2,4-trichlorobenzoleas solvent against closely distributed polypropylene standards. Themolecular weight distribution Mw/Mn (mean weight value/mean numericalvalue) of the polymers was likewise measured by means of the gelpermeation chromatography method and generally amounts to from 1.2 to3.5.

[0028] In addition to all that, the polymers show a glass transitiontemperature Tg within the range of from −50° C. to +30° C., of specialpreference a Tg of from −20° C. to +10° C. The glass transitiontemperature was determined by means of the DSC method.

[0029] The linear, isotactic polymers prepared according to theinvention present, after all, a structure of one or several C₂-C₂₀olefins. In this case, the olefin is preferred to be a C₃-C₂₀-Alk-l-ene.Examples of such C₃-C₂₀-Alk-l-enes are: propene, 1-butene, 2-butene,1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-dodecene,1-hexadecene, 1-octadecene, 1-eicosene.

[0030] Apart from the already mentioned olefins, also C₅-C₂₀cycloolefins are of the especially suitable kind. Examples thereof arecyclopentene, cyclohexene, norbornadiene and its derivatives.

[0031] In case of the linear, isotactic polymers, polypropylene isespecially preferred. Further suitable polymers are copolymers frompropylene and a C₄-C₂₀ olefin or a cycloolefin. It is also possible toprepare terpolymers which show the characteristics defined in patentclaim 1 when they present a structure of propylene, a C₂-C₂₀ olefin anda cycloolefin.

[0032] The polymers prepared according to the invention are e.g. solublein toluol at a temperature within the range of from 20 to 80° C.; theyshow a distinct elastic behaviour in a tensile-strength test, measuredwith a “Standard Universal Testing Machine ZWICK 1445”, as specified inthe examples, and, in general, possess a crystallisation meltingtemperature, measured by means of the “Differential Scanning Calometry”(DSC) method within the range of from −50° C. to 150° C. In particular,it has to be emphasised that, also in this case, the polymers clearlydiffer, in regard of their elastic-thermoplastic behaviour, from thestate-of-the-art, i.e. from European Printed Publication 0 707 016 A1mentioned in the introductory part to the Description. This being so,the polymers prepared according to the invention are particularly suitedfor the manufacture of articles of relatively good deformationresistance, such as e. g. sheathings for household appliances.Furthermore, it is worth mentioning that the polymers can be used inpolymer mixtures for impact resistance modification. Due to theirelastic characteristics, the polymers are especially suited for elasticsheets, moulded bodies, and gaskets.

[0033] The present invention will, hereinafter, be explained in moredetail on the basis of several preparation examples of the catalysts andon the basis of polymerisation examples. Herewith, there show:

[0034]FIG. 1 tensile-strength measurements on two polymers preparedaccording to the invention, as compared to two polymers from EuropeanPrinted Publication 0 707 016 A1,

[0035]FIG. 2 an X-ray structure analysis of a metallocene complexaccording to the invention,

[0036]FIG. 3 a nuclear magnetic resonance (NMR) spectrum of a polymerprepared according to the invention, and

[0037]FIG. 4 a nuclear magnetic resonance (NMR) spectrum of anotherpolymer prepared according to the invention.

[0038]FIG. 1 now illustrates the tensile-strength measurements of twoselected examples from European Printed Publication 0 707 016 A1, ascompared to two polymers prepared in accordance with the invention. Bythe remarks “Cf. FIG. 4” and “Cf. FIG. 5” in FIG. 1, the correspondingexamples from European Printed Publication 0 707 016 A1 are meant inthis case. As can be drawn from a comparison of those tensile-strengthcurves with the tensile-strength curves of the polymers (PP 36 and PP45) prepared according to the invention, the polymers according to theinvention show a distinctive, rubber-elastic plateau. Contrary thereto,the polymers according to European Printed Publication 0 707 016 A1present either a flow behaviour (FIG. 4) or the polymer breaks in caseof higher expenditures of force (FIG. 5). It is just that comparisonthat clearly illustrates the surprising characteristics of the polymersprepared according to the invention and showing a distinctive,rubber-elastic behaviour.

CATALYST PREPARATION Obtaining of 5.6-cyclopenta-2-methyl-indane-1-one

[0039] 40.4 mL of methacryl acid chloride (387.9 mmols) are, togetherwith 62.06 gms of anhydrous aluminium chloride (20 mol % in excess),incorporated into 250 mL of CH₂Cl₂, cooled down to −78 ° C., and slowlymixed with 50.0 mL of indane (45.84 gms, 387.9 mmols). As the indane isadded, the colour changes from bright yellow to orange. The mixture iscarefully quenched with diluted HCl*aq, washed with hydrous K₂CO₃solution and water, and dried through Na₂SO₄.

[0040] Yield: 70.07 gms (376.2 mmols) of oily product, 97.0% of thetheory NMR (200 mcps, CDCl3 7.24 ppm): δ 1.25 ppm d (J=6.9 cps) 3 Hmethyl group, δ 2.10 ppm m (J=3.7 to 7.6 cps) 2 H aliphatic protons ofthe cycles, δ 2.62 ppm m 2 H aliphatic protons of the indanone ring, δ2.86 ppm m (J=11 to 14 cps) 4 H aliphatic protons of the cycles, δ 3.25ppm m (J=7.0 cps) 1 H aliphatic proton of the indanone system, δ7.21 and7.51 ppm s 2 H aromatic MS (GC-MS) m/z 186 (M+ 100%), (186, 251 mol−1).

Obtaining of 5.6-cyclopenta-2-methylindane-1-ole

[0041] 70.07 gms (376.2 mmols) of the 2-methyl-5.6-cyclopentylindane-1-one are, with 5 gms of LiAlH₄, reduced in 200 mL of Et₂0 by lettingthe ketone drip (2 hrs) slowly towards an ice-cooled suspension ofLiAlH₄. Agitating is effected all through the night and quenching withH₂0 is carried out, the colour of the solution changing from lime greento bright yellow. Now 15 mL of HCl are added in concentrated manner andthe emulsion is agitated for 1 h. The etherial phase is separated,neutralised with 200 mL of K₂CO₃ solution, and three times washed withwater.

[0042] Thereafter, drying is effected through Na₂SO₄ and the solvent iscompletely removed. A crystalline mixture of the diastereomeric1-indanoles is obtained. NMR (200 mcps, CDCl₃): δ 1.13 ppm d 3 H methylgroup, δ 1.76 ppm wide 1 H OH group, δ 2.05 ppm m 2 H aliphatic protonsof the cycles, δ 2.15 to 2.71 ppm m 2 H aliphatic protons of theindanole ring, δ 2.87 ppm m 4 H aliphatic protons of the cycles, δ 3.08ppm 1 H aliphatic proton of the indanole system, δ 4.17 and 4.93 ppm d 2H with OH function on the indanole ring, δ 7.08 and 7.23 ppm d 2 Haromatic.

[0043] Yield: 69.62 gms, 369.8 mmols, 98.3% of the theory MS (GC-MS) m/z188 (M+ 100%), (188.267 gms mol⁻¹).

Obtaining of 5.6-cyclopenta-2-methylindene

[0044] 69.62 gms (369.8 mmols) of the diastereomer mixture of the2-methyl-5.6-cyclopentylindene-1-oles are dissolved in 500 mL ofbenzole; and then 3 to 5 gms of p-TosOH are added and the emulsion is,for three quarters of an hour, boiled on the water separator underreflux. The organic phase is separated, neutralised with 200 mL of K₂CO₃solution, and three times washed with water. Thereafter, drying iseffected through Na₂SO₄ and the solvent is completely removed.

[0045] The product colourlessly crystallises from n-pentane; yield:57.67 gms, 338.7 mmols corresponding to 91.6% of the theory, MS (GC-MS)m/z 170 (M+ 100%), (170.225 gms mol⁻¹). NMR (200 mcps, CDCl3 7,24 ppm):δ 2.23 ppm m/s 5 H methylene and 2-methyl group of the indene system, δ3.01 ppm t 4 H methylene groups, δ 3.32 ppm s 2 H methylene group acids,δ 6.51 ppm s 1 H olefinic indene system, δ 7.20 and 7.34 ppm s 2 Haromatic, 13-NMR (200 mcps, CDCl₃): δ 16.8 ppm methyl group, δ 25.8 ppmmethylene group of Cycle 5, δ 32.66 and 32.72 ppm methylene groups ofthe Cycle, δ 42.2 ppm methylene group of the indene system, δ 127.1 ppmtertiary C-atom of the indene system, δ 115.5 and 119.5 (each with H)ppm aromatic C-atoms, the same without H for 139.6, 141.7, 142.1, 144.4,and 145.0 ppm incl 4° olefinic C-atom of the indene system (cf. CHcorrelation and HH-COSY).

Obtaining of 1-(9 fluorenyl)-2(1-(5.6-cyclopenta-2-methyl)indenyl)ethane

[0046] 3.89 gms of 2-methyl-5.6-cyclopentylindene-1 (22.85 mmols) are,with 14.3 mL of n-BuLi, deprotonated in 150 mL of dioxane and then mixedwith a solution of 25.13 mmols of 2-(9′-fluorenyl) ethyltrifluoromethanesulphonate in 100 mL of dioxane. Agitating is effected all through thenight, heating up to 60° C. is carried out for half an hour and thesolution is quenched with ca. 3 mL of H₂0. The dioxane is removed andthe product is extracted with three times 200 mL of Et₂0. Withoutchromatographic processing, 6.49 gms (17.9 mmols, 78.3% of the theory)of a colourless, crystalline Product are obtained.

[0047] NMR (200 mcps, CDCl3, 7.24 ppm): δ 1.89 ppm s 3 H methyl group, δ1.41 ppm to 1.72 ppm m 4 H aliphatic protons of the bridge, δ 2.10 ppmpseudo-t 2 H aliphatic protons of the cycle, δ 2.90 ppm pseudo-t 4 Haliphatic protons of the cycle, δ 8.37 ppm t 1 H aliphatic proton of thefluorene system, δ 6.40 ppm s 1 H indene proton, δ 6.98 and 7.07 ppmaromatic protons of the indene system, δ 7.31 to 7.77 ppm m 8 H aromaticof the fluorene. MS (FD) m/z 362.5 (M+ 100%

Obtaining of 1-(9 fluorenyl)-2-(1-(5.6-cyclopenta-2-methyl) indenyl)ethane zirconocene dichloride

[0048] 1.711 gms of 1-[1′-(2′-methyl)5′,6′-cyclopentylindenyl-2-(9″-fluorenyl)]ethane (4.72 mmols) are dissolvedin 100 mL of toluol, mixed with 10 mL of dioxane, and deprotonated, atlow temperature, with 5.9 mL of n-BuLi. Agitating is effected for ca. 1hour and then the suspension is again cooled down to −78° C. Now 1.10 gmof ZrCl₄ is added. That suspension is agitated, at room temperature, foranother 14 hours, in which case a fine red powder forms that can becrystallised after a separation of formed LiCl from toluol.

[0049] Yield: 2.148 gms (4.11 mmols, 87.1% of the theory). NMR (500mcps, C₂D₂Cl₄ 80° C.); δ 2.00 ppm m 2 H methylene group cyclopentanering (J=6.8 to 7.5 cps),.δ 2.15 ppm s 3 H methyl group, δ 2.79 to 2.94ppm m 4 H methylene groups cyclopentane ring adjacent to the aromaticsystem (J=7.5 to 9.7 cps), δ 4.05 ppm m (J=3.5 to 13.2 cps) 2 Haliphatic protons of the bridge (in case of the fluorene), δ 3.83 and4.57 ppm m (J=4.2 to 10.0 cps) 1 H aliphatic protons of the bridge(diastereotopic) at a time, δ 6.05 ppm s 1 H indene proton, δ 7.03 to7.85 ppm m 10 H aromatic. MS (E1) m/z 5, 22, 6 isotopic patterncorresponding EA CH-combustion analysis: calculated 64.35% C 4, 63 % HFound: 64.08/63.89% 4.53/4.63%

POLYMERISATION EXAMPLE

[0050] All the polymerisations were carried out in 300 mL of toluolunder the conditions indicated in Table 1.

[0051] The NMR data were measured by means of a Bruker AMX 500 deviceand evaluated on the basis of literature data. TABLE 1 TP C3 Yield tp TgTm Run No. Catalyst Amount# [° C.] [mol-1] [g] [min] Activity* [° C.] [°C.] Mw Mw/Mn P36 Flu-Et-Ilnd 7.5 30 2.9 36.87 33 3080 −5.9 50.2 171.0001.96 P45 FIu-Et-Ilnd 10 35 4.92 115.23 39 3603 −7.5 51.7 95.700 1.74Pentoden Run No. in % mmmm mmmr rmmr mmrr mmrm + rmrr rmrm rrrr rrrmmrrm Al/Zr P36 36.7 18.5 2.1 21.1 5.0 0.0 2.5 3.7 10.3 2000 P45 36.517.9 1.7 21.0 5.8 0.3 3.1 3.6 10.1 2000

1. A catalyst combination for preparing linear isotactic polymers, saidcatalyst combination containing a metal complex of general Formula I

wherein the substituents have the following significations: R¹-R⁷ linearor branched C₁ to C₁₀ alkyl, 5- to 7-linked cycloalkyl which, in itsturn, can carry one or several C₁ to C₆ alkyl residues as substituent,C₆ to C₁₈ aryl or arylalkyl or alkylaryl, in which case R¹/R², R³/R⁴,R⁶/R⁷ can be partially or simultaneously integrated into 5- to 7-linkedcycloalkyl or aryl rings fused thereto; R⁹, R¹⁰ C₁ to C₈ alkyl, 4- to7-linked cycloalkyl, aryl, in which case R⁹, R¹⁰ can, jointly with E,form a 4- to 7-linked cycloalkyl or aryl; R¹¹ C₁ to C₈ alkyl, aryl, C₁to C₈ oxyalkyl, C₁ to C₈ trialkylsiloxy; M titanium, zirconium, hafnium,vanadium, niobium, tantalum; X halogen or C₁ to C₈ alkyl, aryl, benzyl;E carbon, silicon, germanium or 1.2-ethyl 1.3-propyl, 1.4-butyl; and anactivator.
 2. A catalyst combination as well as an activator accordingto claim 1, characterised in that the activator is an open-chain orcyclic alumoxane compound of general Formula II or III

R⁸ standing for a C₁ to C₄ alkyl group and n standing for a numberbetween 5 and 30, and/or a cationic activator of general Formulas IV toVI B(C₆F₅)₃   (IV) R⁹ ₃C[B(C₆F₅)₄]  (V)[R⁹ ₃NH ][B(C₆F₅)₄]  (V) R⁹signifying a C₁ to C₄ alkyl group or an aryl group.
 3. A catalystcombination according to claim 1 or 2, characterised in that the metalcomplex according to general Formula I is a compound of general FormulaVII

wherein the residues R¹ to R¹¹ have the significations indicated ingeneral Formula I and E²═CH₂, O or S and n=1 or
 2. 4. A catalystcombination according to at least one of claims 1 to 3, characterised inthat the metallocene complex of general Formula I and the activatoraccording to general Formulas II to VI are utilised in such quantitiesthat the atomic ratio between aluminium from the alumoxane and/or boronfrom the cationic activator and the transition metal from themetallocene complex is within the range of from 1:1 to 10⁶:1.
 5. Aprocess for preparing linear, isotactic polymers which have a structureof which the tacticity varies within the range of between 25 and 60% of[mmmm] pentad concentration, an arbitrary or rather regular sequence ofisotactic and atactic blocks being excluded, in which process a C₂ toC₂₀ olefin are reacted with a catalyst combination being defined inclaim 1 to
 4. 6. A process according to claim 5, characterised in thatthe polymerisation reaction is carried out in the gas phase, insuspension or in supercritical monomers, especially in solvents inertunder the polymerisation conditions.
 7. A process according to claim 5or 6, characterised in that, as inert solvents, solvents are used thatdo not contain any reactive molecules, such as e.g. benzole, toluol,xylol, ethyl benzole or alkanes such as e.g. propane, n-butane,i-butane, pentane, hexane, heptane or mixtures thereof.
 8. A processaccording to at least one of claims 5 to 7, characterised in thatpolymerisation is carried out at pressures of from 1 to 100 bars,preferably from 3 to 20 bars and especially from 5 to 15 bars, and attemperatures of from −50 to 200° C., of preference from 10 to 150° C.and especially at from 20 to 40° C.